As this kind of electromagnetic switch, there is proposed, for example, a hermetic type relay device wherein a spatial cavity is formed by a ring-like core base upper portion, a ring-like core base bottom portion, and a core external wall linking outer peripheral edges of the core base upper portion and core base bottom portion, and an exciting coil is mounted inside the spatial cavity. Also, a core assembly is formed by inserting a cylindrical core center through a central aperture in the core base upper portion, a bottomed cylindrical member is fitted onto the outer peripheral portion of the core center, a movable plunger that opposes the lower surface of the core center across a predetermined gap is disposed inside the bottomed cylindrical member, and an armature shaft that extends upward through the core center and holds a movable contact is fixed in the plunger (for example, refer to Patent Document 1).
Also, there is proposed an electromagnetic switching device that has a configuration wherein a first yoke and second yoke having cylindrical portions individually fitted inside a cylindrical portion of the bobbin on an upper portion side and lower portion side of a bobbin having flange portions, and flange portions formed on the outer side of the cylindrical portions, are disposed at both ends of a cylindrical, portion in which an exciting coil is wound, a movable core is slidably disposed on the inner peripheral surface of the second yoke, and a movable contact is held in the movable core via a connecting shaft (for example, refer to Patent Document 2).